Change QuicStreamSequencer's destructor to be a non-virtual.

It's the only virtual method in the class, so this will removes the vtable and make function calls faster.

PiperOrigin-RevId: 487617907

quiche/quic/core/quic_stream_sequencer.h

diff --git a/quiche/quic/core/quic_stream_sequencer.h b/quiche/quic/core/quic_stream_sequencer.h
index 027b2e0..f0e3ab3 100644
--- a/quiche/quic/core/quic_stream_sequencer.h
+++ b/quiche/quic/core/quic_stream_sequencer.h
@@ -22,7 +22,7 @@
 
 // Buffers frames until we have something which can be passed
 // up to the next layer.
-class QUIC_EXPORT_PRIVATE QuicStreamSequencer {
+class QUIC_EXPORT_PRIVATE QuicStreamSequencer final {
  public:
   // Interface that thie Sequencer uses to communicate with the Stream.
   class QUIC_EXPORT_PRIVATE StreamInterface {
@@ -59,7 +59,7 @@
   QuicStreamSequencer(QuicStreamSequencer&&) = default;
   QuicStreamSequencer& operator=(const QuicStreamSequencer&) = delete;
   QuicStreamSequencer& operator=(QuicStreamSequencer&&) = default;
-  virtual ~QuicStreamSequencer();
+  ~QuicStreamSequencer();
 
   // If the frame is the next one we need in order to process in-order data,
   // ProcessData will be immediately called on the stream until all buffered